Clock signals, which oscillate periodically, are used in many electronic circuits and for a multitude of reasons. An oscillator can provide a periodic clock signal. A clock signal of a lower frequency may also be generated by providing the oscillator output to a divider that outputs a clock signal whose frequency is a fraction of the oscillator frequency. Many electronic circuits use multiple clock signals having different frequencies. One way to generate such clock signals is to provide the oscillator output to a clock-processing circuit having one or more dividers, each divider receiving the oscillator output as an input, and one or more delay elements, where the oscillator output is used by the clock-processing circuit as a base signal of relatively-high frequency to generate clock signals of various frequencies and/or phases.
Some electronic circuits, such as certain RAM circuits, require that a first clock signal be a particular number of radians out-of-phase with a second clock signal. The requisite phase difference may be hardwired into the circuit. Alternatively, the requisite phase difference may be dynamically controlled and generated while the electronic circuit is operating. Some prior-art circuits can only delay and not advance the phase of the second clock signal relative to the first. Some prior-art circuits require resetting the dividers of the clock-processing circuits in order to achieve a desired relative phase delay.